One or more embodiments of the subject matter described herein relate to distance and/or motion sensing systems and methods, such as radar and/or optical remote sensing systems and methods.
Known radar systems transmit analog electromagnetic waves toward targets and receive echoes of the waves that reflect off the targets. Based on the distance between antennas that transmit the analog waves and the target objects, and/or movement of the target objects, the strength and/or frequency of the received echoes may change. The strength, frequency, and/or time-of-flight of the echoes may be used to derive the distance to the targets and/or movement of the targets.
Some known radar systems are limited in the accuracy at which the systems can measure distances to the targets. For example, the resolution at which these systems may be able to calculate the distance to targets may be relatively large. Moreover, some of these systems may have circuitry, such as a transmit/receive switch, that controls when the systems transmit waves or receive echoes. The switch can require a non-zero period of time to allow the systems to switch from transmitting waves to receiving echoes. This period of time may prevent the systems from being used to measure distances to targets that are relatively close, as the transmitted waves may reflect off the targets back to the receiving antennas before the systems can switch from transmission to reception. Additionally, some known systems have energy leakage from the transmitting antenna to the receiving antenna. This energy leakage can interfere with and/or obscure the measurement of distances to the targets and/or the detection of motion.